Custom UIView Class : Using getter/Setter methods

blueFLoyd8 · 07-11-2009, 05:36 PM

Howdy!
I created a UIView so that I can easily add a customized object multiple times without using much code. The view object is a blue box with some dynamic text labels.
All of the code is working except I cannot edit the properties of the objects within the UIView. Take a look at the titleLbl object:

Main Class.m
This code successfully adds the blueBox, however I cannot change the text of the label to @"Hello World". The code initializes the label to say "hello, cosmos", but then I can't change this.

Code:

blueBox = [[blueBoxObject alloc] initWithFrame:CGRectMake(10,200,200,100)];
//[[blueBox titleLbl]setText:@"Hello World"];
blueBox.titleLbl.text = @"Hello, World!";
[self.view addSubview:blueBox];

blueBoxObject.h

Code:

@interface blueBoxObject : UIView {
	UIImageView *box;
	UILabel *titleLbl;
	UILabel *textLbl;
}
@property (nonatomic, retain) UILabel *titleLbl;
@property (nonatomic, retain) UILabel *textLbl;

blueBoxObject.m

Code:

- (void)drawRect:(CGRect)rect {
    // Drawing code
	box = [[UIImageView alloc] initWithFrame:CGRectMake(0,0,BOX_W,BOX_H)]; 
	[box setImage:[UIImage imageNamed:@"btnBlue.png"]];
	box.opaque = YES;
	[self addSubview:box]; 
	
	titleLbl = [[UILabel alloc] initWithFrame:CGRectMake(15,15,BOX_W-30,40)];
	titleLbl.backgroundColor = [UIColor clearColor];
	titleLbl.textColor = [[UIColor alloc] initWithRed:0.7 green:0.16 blue:0.1 alpha:1.0];
	titleLbl.font = [UIFont fontWithName:@"Helvetica-Bold" size:32];
	titleLbl.textAlignment = UITextAlignmentLeft;
	[titleLbl setText:@"Hello, Cosmos"];
	[self addSubview:titleLbl];
}

Thanks for the help everyone!

Stitch · 07-12-2009, 02:33 AM

Hi,

If you are using "@property (nonatomic, retain) UILabel *titleLbl;" then you need to make sure you use "self." otherwise you don't correctly go through the setter method.

eg:

Code:

UILabel *tempTitleLbl = [[UILabel alloc] initWithFrame:CGRectMake(15,15,BOX_W-30,40)]; // alloc the object here
self.titleLbl = tempTitleLbl; // pass the object through the setter so it's retained
[tempTitleLbl release]; // release the object that you allocated
titleLbl.backgroundColor = [UIColor clearColor];
titleLbl.textColor = [UIColor colorWithRed:0.7 green:0.16 blue:0.1 alpha:1.0]; // remove alloc from here as you are not releasing
titleLbl.font = [UIFont fontWithName:@"Helvetica-Bold" size:32];
titleLbl.textAlignment = UITextAlignmentLeft;
[titleLbl setText:@"Hello, Cosmos"];
[self addSubview:titleLbl];

I'm not sure if it's required but I always update my strings from inside the actual View, not the main class:

Code:

- (void)myCustomUpdateLabelWithString:(NSString *)aString {
titleLbl.text = aString;
}

Don't forget to put this in your view header:

Code:

- (void)myCustomUpdateLabelWithString:(NSString *)aString;

Then just call this from your main class to update:

Code:

[blueBox myCustomUpdateLabelWithString:@"Updated String"];

blueFLoyd8 · 07-12-2009, 01:43 PM

That is not working for me. The NSLog statement in the updateTitle function prints the string value but the label does not get changed. Here is what I tried:
blueBoxObject.m

Code:

- (void)drawRect:(CGRect)rect {
    // Drawing code
	box = [[UIImageView alloc] initWithFrame:CGRectMake(0,0,BOX_W,BOX_H)]; 
	[box setImage:[UIImage imageNamed:@"btnBlue.png"]];
	box.opaque = YES;
	[self addSubview:box]; 
	UILabel *tempLabel = [[UILabel alloc] initWithFrame:CGRectMake(15,15,BOX_W-30,40)];
	self.titleLbl = tempLabel;
	[tempLabel release];
	self.titleLbl.backgroundColor = [UIColor clearColor];
	self.titleLbl.textColor = [[UIColor alloc] initWithRed:0.7 green:0.16 blue:0.1 alpha:1.0];
	self.titleLbl.font = [UIFont fontWithName:@"Helvetica-Bold" size:32];
	self.titleLbl.textAlignment = UITextAlignmentLeft;
	[self.titleLbl setText:@"temp"];
	[self addSubview:self.titleLbl];
}
- (void) updateTitleWithString:(NSString*)title {
	NSLog(@"updating. title = %@", title);
	[self.titleLbl setText:title];
}

Blueboxobject.h

Code:

@interface blueBoxObject : UIView {
	UIImageView *box;
	UILabel *titleLbl;
}
@property (nonatomic, retain) UILabel *titleLbl;

- (void) updateTitleWithString:(NSString*)title;

Main Class.m[

Code:

blueBox = [[blueBoxObject alloc] initWithFrame:CGRectMake(10,200,200,100)];
		//blueBox.titleLbl.text = @"Hello, World!";
		[blueBox updateTitleWithString:@"Danny"];
		[self.view addSubview:blueBox];

Stitch · 07-12-2009, 02:42 PM

You only put "self." when you pass the object to it for retaining:

Code:

UILabel *tempLabel = [[UILabel alloc] initWithFrame:CGRectMake(15,15,BOX_W-30,40)];
self.titleLbl = tempLabel;
[tempLabel release];

Everything else you can leave without it:

Code:

- (void)drawRect:(CGRect)rect {
    // Drawing code
	box = [[UIImageView alloc] initWithFrame:CGRectMake(0,0,BOX_W,BOX_H)]; 
	[box setImage:[UIImage imageNamed:@"btnBlue.png"]];
	box.opaque = YES;
	[self addSubview:box]; 
	UILabel *tempLabel = [[UILabel alloc] initWithFrame:CGRectMake(15,15,BOX_W-30,40)];
	self.titleLbl = tempLabel;
	[tempLabel release];
	titleLbl.backgroundColor = [UIColor clearColor];
	titleLbl.textColor = [[UIColor alloc] initWithRed:0.7 green:0.16 blue:0.1 alpha:1.0];
	titleLbl.font = [UIFont fontWithName:@"Helvetica-Bold" size:32];
	titleLbl.textAlignment = UITextAlignmentLeft;
	[titleLbl setText:@"temp"];
	[self addSubview:titleLbl];
}
- (void) updateTitleWithString:(NSString*)title {
	NSLog(@"updating. title = %@", title);
	[titleLbl setText:title];
}

Stitch · 07-12-2009, 02:43 PM

Again, I don't think you should do this:

Code:

[[UIColor alloc] initWithRed:0.7 green:0.16 blue:0.1 alpha:1.0];

Try without the "alloc". I think it's:

Code:

[UIColor colorWithRed:0.7 green:0.16 blue:0.1 alpha:1.0];

blueFLoyd8 · 07-12-2009, 03:13 PM

Still not working. The NSLog statement confirms that the parameter string is being passed.

Code:

- (void)drawRect:(CGRect)rect {
    // Drawing code
	box = [[UIImageView alloc] initWithFrame:CGRectMake(0,0,BOX_W,BOX_H)]; 
	[box setImage:[UIImage imageNamed:@"btnBlue.png"]];
	box.opaque = YES;
	[self addSubview:box]; 
	UILabel *tempLabel = [[UILabel alloc] initWithFrame:CGRectMake(15,15,BOX_W-30,40)];
	self.titleLbl = tempLabel;
	[tempLabel release];
	titleLbl.backgroundColor = [UIColor clearColor];
	titleLbl.textColor = [UIColor colorWithRed:0.7 green:0.16 blue:0.1 alpha:1.0];
	titleLbl.font = [UIFont fontWithName:@"Helvetica-Bold" size:32];
	titleLbl.textAlignment = UITextAlignmentLeft;
	[titleLbl setText:@"temp"];
	[self addSubview:titleLbl];
}
- (void) updateTitleWithString:(NSString*)title {
	NSLog(@"updating. title = %@", title);
	[titleLbl setText:title];
}

Stitch · 07-12-2009, 03:29 PM

Try taking your code out of drawRect and putting it in your own function:

Code:

- (void)createLabels {

<code here>

}

Then call this from your init in the view:

Code:

[self createLabels];

This way you know that the labels will be created when you init the view.

I think you're trying to set the label before it actually exists.

blueFLoyd8 · 07-12-2009, 08:35 PM

Quote:

Originally Posted by Stitch

I think you're trying to set the label before it actually exists.

You were right. It turns out that drawRect() was getting called later. I am not sure why I even need this function. I moved the code to initWithFram() instead and it works now.
Thanks!

Code:

- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        // Initialization code
    }
	self.backgroundColor = [UIColor clearColor];
	self.opaque = YES;
	box = [[UIImageView alloc] initWithFrame:CGRectMake(0,0,BOX_W,BOX_H)]; 
	[box setImage:[UIImage imageNamed:@"btnBlue.png"]];
	box.opaque = YES;
	[self addSubview:box]; 
	[self drawLabels];
    return self;
}

- (void) drawLabels {
	NSLog(@"Draw labels");
	UILabel *tempLabel = [[UILabel alloc] initWithFrame:CGRectMake(15,15,BOX_W-30,40)];
	self.titleLbl = tempLabel;
	[tempLabel release];
	titleLbl.backgroundColor = [UIColor clearColor];
	titleLbl.textColor = [UIColor colorWithRed:0.7 green:0.16 blue:0.1 alpha:1.0];
	titleLbl.font = [UIFont fontWithName:@"Helvetica-Bold" size:32];
	titleLbl.textAlignment = UITextAlignmentLeft;
	[titleLbl setText:@"temp"];
	[self addSubview:titleLbl];
}

grosch · 06-29-2010, 11:14 PM

You're leaking a reference here. When you call [UILabel alloc] you get a retain count of 1. When you assign to self.titleLbl it goes up to 2, which is why you then release it to go back to 1. Good stuff.

However, later you pass that into [self addSubview:titleLbl] which ups the reference count to 2 again. So you need to do one more release after the addView to get it back down to 1 again.